Here is my problem, my ac blows cold air but it does not blow through the vents, is blows out the door vents, and the passenger vents but not the vents on the dash. Anyone have an Idea how to fix or what is causing the problem, I would appreciate any input. My car is a 2000 Deville, thanks

 

check for a loose vacuum connection below the dash near the steering column.

 

Hello!

I am having a similar problem. When I accelerate, the air vents on the dash stop blowing cold air! The A/C works fine. Once the car is at cruise speed or at idle and no acceleration is going on, the dash vents operate and cold air comes out.

Is this beyond bizarre or what?

I am wondering if the under-dash a/c ductwork is controlled by vacuum-operated values/dams/doors?

It reminds me of the old vacuum operated windshield wipers -- I can't remember now whether going faster made the wipers go faster, but somehow, the engine affected the vacuum.

Does the '97 Caddy DeVille use engine vacuum? Does it have a separate vacuum pump? How can I track this down?

Oh, yes, another thing, the parking brake will not automatically release.

This is all new. I had the head gaskets replaced ($$$) on this car recently and I think a few things did not get reconnected properly.

Thanks,

Chuck

 

I have experienced the same problem. Usually it is a loose vacuum line. In my instance, the vacuum line was in the engine compartment along the firewall leading to the vacuum cannister. Hard to tell you where to check, but look over all the visible vacuum line closely. Also, check any t-connectors on the vacuum line junctions which might have cracked, but still look intact. Good luck.

 

Blend door motor. See my post for an easy fix.